Generally, the need to control access to outside telephone lines in an institutional environment is well recognized. In order to prevent individuals from incurring large, unaccountable telephone costs which the institution ultimately bears, one must either restrict access to outside telephone lines or institute accounting controls whereby the costs of unauthorized calls can be billed to the responsible individuals.
Telephone systems in correctional environments require additional security considerations. Without appropriate controls on telephone access, inmates have been known to use the telephones to harass outside parties (such as witnesses who testified against them, attorneys who prosecuted their case, employees of the courts, etc.), to perpetrate fraudulent schemes, and to participate in criminal conspiracies (such as arranging the smuggling of contraband into the prison, directing an outside criminal enterprise, plotting escape attempts or credit card fraud). Therefore, it is critically important for correctional management officials to carefully plan, control, monitor and record inmate access to outside telephone lines.
One of the most fundamental problems--which exists both in correctional and other business-oriented institutions--is cost control. To achieve cost control, it is critical that there be individual accountability for each call that incurs a charge to the institution. Such accountability is typically achieved through use of personal identification numbers ("pins"). Before making a call from an institution telephone, an individual must enter his PIN. The telephone service provider is then able to deliver to the institution an end-of-the-month telephone bill which lists, in addition to the cost of each call, the PIN or name of the individual who made the call. From this information, the institution can then collect reimbursement from individuals for the costs of certain calls.
While this system of end-of-the-month call accounting functions reasonably effectively in a business like environment, it does not work well in a penal institution. The reason is that inmates show little concern for phone bills they can't afford to pay. Thus, the institution is often forced to absorb the costs of phone calls by its delinquent inmates. Moreover, the fact that account balances are only computed periodically--i.e., every month, week, or even every day--permits the inmate to accrue large, uncollectible phone bills before his access to the phones can be terminated. Traditionally, penal institutions have addressed this problem by restricting inmates to collect calls only. This, however, still provides the inmates with relatively unlimited access to the outside world, leaving open numerous opportunities for fraudulent and criminal activity, as explained below. Therefore, in a penal environment, it is highly desirable to regulate phone access on an individual, pay-in-advance basis, and to immediately and automatically terminate an individual's phone access when his/her paid-up account reaches a zero balance.
Another problem in penal institutions is the inmates' desire to make threatening or harassing phone calls to witnesses, prosecutors, police officers, parol officers, psychologists, judges, and the relatives and family of such persons. Limiting the inmates' access to collect calls only, does not effectively address this problem, since an inmate can easily identify himself (to an operator) as someone from whom the recipient would likely accept a collect call. Rather, one should, at a minimum, provide a means that permits a potential call recipient to identify the caller as an inmate before accepting the call, whether that call is placed on a prepaid or collect basis. Conventionally, this is done by initially placing the inmate on hold and playing a pre-recorded message telling the recipient that a call has been placed from a correctional facility and that, if the recipient wishes not to receive the call, he/she should hang up before the call is connected. This approach mitigates, but does not fully solve, the harassment problem. In particular, it is still possible for an inmate to repetitively call an outside party; even if the recipient hangs up after hearing the pre-recorded message, the harassing effect of receiving repetitive calls from inside the correctional institution remains. Therefore, it would be highly desirable to provide an institutional telephone system that automatically prohibits inmates from attempting to call certain outside persons. Moreover, it would also be highly desirable to provide a method and apparatus for allowing a recipient of an undesired call from an inmate to easily and automatically prohibit all future calls from that particular inmate, or from all inmates generally.
Still another concern in correctional institutions is the regulation of access to telephone systems. For various security and management reasons, it often desirable to restrict a given inmate's telephone access to particular phones, calling times, and to limit the length of calls, number of calls, and number of calls to the same number. Also, to enhance security and discipline, it should be possible to instantaneously revoke an inmate's calling privileges, or to otherwise modify the extent of a particular inmate's calling privileges.
Correctional institutions also typically wish to monitor and/or record outgoing calls. Inmate-to-attorney calls, however, cannot legally be monitored or recorded. Moreover, certain inmates--those who represent particular security risks--deserve live monitoring, as opposed to mere recording. Thus, it would be highly desirable to have a system which automatically initiates the appropriate monitoring and/or recording depending upon the identity of the inmate placing a call and the recipient of the call (i.e., attorney or non-attorney). Likewise, it may be desirable that calls to certain numbers are to be monitored live, while others need only be recorded.
Because the message content of inmate-to-attorney calls cannot be legally recorded or monitored, such calls can serve as a conduit for the inmate's illegal telephone activity. Therefore, it would be highly desirable to have a system which could passively--that is, without in any way monitoring or recording what is actually being said--monitor inmate-to-attorney calls to ensure that: (1) the only two people speaking on the line are the inmate and attorney, and/or (2) no DTMF tones, rapid line impedance changes, off-hook conditions or voltage spikes appear on the line. Techniques for voice identification are known--i.e. U.S. Pat. Nos. 4,993,068, entitled UNFORGEABLE PERSONAL IDENTIFICATION SYSTEM and 5,150,357, entitled INTEGRATED COMMUNICATIONS SYSTEM, both incorporated herein by reference--but have not been previously used in penal telecommunications applications.
One patent, U.S. Pat. No. 4,726,057 to Doerry et al. explained many of the problems brought about by the deregulation of the telephone industry in the United States. That patent states: "Prior to a June, 1984 FCC decision, pay telephones were the exclusive province of the various Telephone Companies while others were precluded from the business of providing pay telephone service. Today, however, subject to state Public Utility Commission regulations, Customer Owned Coin Telephone (COCOT) service is permitted, but a number of non-trivial technical challenges have been created including called party answer detection.
Coin telephones (pay phones) owned by the local Telephone Company generally utilize DC signals to signal called party answer. Such information is specially communicated between telephone central offices and then to the originating pay phone telling it when to accept the deposited coins. Such information, however, is not communicated to conventional telephones and it is only with great difficulty that called party answer can be detected. Naturally, the calling party knows when a connection is completed; but a knowledge of human frailty suggests that he not be relied upon to turn the "meter" on.
Complicating the problem of answer detection is the existence of special information messages that are provided when, for example, a telephone has been disconnected or a new telephone number has been assigned; and while certain tones are indicative of a proper answer, other tones are not. Ringing, busy and reorder signals as well as background noise and feedback from the calling party herself (sidetone) make answer detection a formidable challenge."
The problems set forth above are exacerbated by the fact that callers, such as inmates in a prison, have the ability to work in concert with others outside of the facility. For example, an inmate may be restricted from calling a particular judge who sentenced him, however, that inmate may call his spouse, who in turn may set up a conference call to the judge, thus allowing the inmate to verbally abuse the judge. Such a conference call may be prohibited by law, however, the correctional facility cannot prevent it, as the called party, in this case, the spouse, has the ability to bridge callers with other outside, unrestricted telephone lines, thus giving the inmate unrestricted telephone access.
Present attempts to solve the problem of called party bridging, or so-called third party calls, have shortcomings. For example, one attempt at resolving this problem is disclosed in U.S. Pat. No. 5,319,702, to Kitchin et al. In that patent, the need to provide an apparatus for use in conjunction with so-called "local equipment/telephone." When the local equipment/telephone is in telecommunication with a remote telephone, (i.e., when a telephone call is established therebetween), the apparatus is capable of indicating whether the remote party has performed a specific act causing the generation of a hook flash-type signal which is detected by the apparatus. In that patent, the detection of a hook flash-type signal is presumed to solve the problem of unauthorized calls to third parties, such as a telephone call from an inmate to the judge who sentenced him, as set forth above. The apparatus of that patent includes a band filter for passing energy having certain frequencies and an energy detector for detecting a specific electrical energy pulse having been filtered by, i.e. passed through the filter, and having a predetermined minimum magnitude. The apparatus of that patent further describes in part software (referred to as window analyzation means) which cooperates with the energy detector to detect a specific event(s) occurring on the telephone line during a predetermined maximum time window following the detection of a specific pulse on the telephone line, i.e., when a telephone call is in progress between the local party/equipment and the remote party. The detection of a specific event(s) on the line provides an indication as to whether the remote party has performed a specific act such as (1) attempting to initiate a 3-way conference call, (2) accepting a call or the charges therefor, (3) terminating a call before the local equipment/party terminates the call, and (4) dialing a specific number on a remote rotary/pulse telephone. Further, the apparatus of that patent is said to be suitable for use in a computer controlled telephone wherein the energy detector detects when a called party has answered a call initiated by the computer operated telephone and dialed a pulse/dial telephone or activated (flashed) the hookswitch. The energy detector is said to do this by measuring incoming electrical signal energy in a particular frequency band. Then, according to that patent, the software window analyzer cooperates with the energy detector to provide efficient and reliable protection of a called party's pulse dialing of a digit (usually a "zero") to verify the called party's acceptance of a call or a collect call or the called party's attempt to activate 3-way calling by flashing the called party's telephone hookswitch.
The energy detector of U.S. Pat. No. 5,319,702 to Kitchin et al. is also said to include an absolute value level detector circuit that determines when an energy pulse having passed through the band filter is above a predetermined level. If above a predetermined level, the information is transmitted by the energy detector to the apparatus' controlling computer. As previously mentioned, the apparatus further includes software, i.e., the aforementioned window analyzer, for cooperating with the energy detector to detect specific event(s) occurring on the telephone line during a predetermined maximum time window following a detection of the specific pulse. In the situation where the apparatus according to that patent is said to be designed or programmed to detect a remote party's attempt to initiate a 3-way conference call, the software window analyzer is said to include a timer or timer means for cooperating with the energy detector so that the timer begins running for a first predetermined period when a specific energy pulse is detected by the energy detector. The software window analyzer also includes sound detection means for detecting sound on a telephone line and for cooperating with the timer so that the sound detection means is activated at the end of the first predetermined period for a second predetermined maximum time period. If sound is not detected during the second predetermined time period, such indicates that the remote party has attempted to initiate a 3-way conference call.
Kitchin discloses a type of energy detector that can also incorporate a ringback detector--not to activate third party call blocking, but merely for activating the energy detector when the ringback signal is detected. Thus, the ringback detector is used to set the energy detector, so that the energy detector can purportedly carry out the purpose of that patent, and so that the energy detector can be utilized. Indeed, Kitchin states that "t!hose skilled in the art will appreciate that called party answer is indicated when the first specific energy pulse is detected after the apparatus has detected the called party's ringback signal." Thus, the ringback signal is used to initialize the Kitchin system--not to solve the problem at hand. In that sense, Kitchin teaches away from relying upon the use of ringback detection as a means to block third party calls.
The Kitchin patent discloses "being useful for detecting certain specific events, i.e., call answer, an attempt to initiate a 3-way conference call, call acceptance, call termination, and determining the specific number dialed number on a rotary/pulse telephone. Any event which causes the generation of the hook flash-type signal such as a call waiting signal can purportedly be detected. Importantly, Kitchin says that it can detect "any event which causes the generation of the hook flash-type signal". This is important because that is the entire focus of the Kitchin patent--to detect hook flashes, or the energy pulses associated therewith. This approach is problematic, as it relies on the detection of a pulse--not the detection of certain tones. While the Kitchin patent may appear to be an elegant solution to the problem of blocking third party calls, it is needlessly complex, and if anything, complicates the process of detecting the attempted establishment of third party calls. The prior art does not teach the simple, direct method of sensing third party call patterns by merely monitoring the occurrence of tones that called parties traditionally generate in their efforts to bridge callers with third parties. In essence, many called parties allow the caller to be on the line while they dial the third party--that is an opportunity to sense DTMF tones. Then, many called parties may dial the wrong number of the third party, and a SIT tone will indicate that number may have been disconnected, subject to an area code change, or the like--all while the caller is on the line. That is another opportunity for sensing tones to prevent third party calls. Also, called parties may use a credit card to call third parties--also while the caller is on the line. Call progress tones may be generated during such credit card calls--thus, yet another opportunity to sense tones to prevent third party calls. Also, if at any time during the call, a ring or busy signal is heard on the caller's telephone, still another opportunity is present for sensing tones to prevent third party calls. And finally, if at any time during the call while the inmate is on the line, a dial tone occurs (as when a called party may go off-hook to place the call to the third party), yet another opportunity exists for sensing tones to prevent third party calls.